Biological effects of contaminants: Use of imposex in the dogwhelk (<i>Nucella lapillus</i>) as a bioindicator of tributyltin pollution

This document describes a method for detecting contamination of the marine environment by tributyltin (TBT) using a sensitive neogastropod, the dogwhelk Nucella lapillus (L.), as a bioindicator. Exposure of female N. lapillus to TBT induces masculinization; this induction of masculinization has been termed 'imposex'. The indices that have been employed to measure imposex in N. lapillus are described here, together with a brief account of the biology of this organism.